1. Field of the Invention
The present invention relates generally to a memory device, and particular, a memory device for a mobile phone having a large capacity at low cost.
2. Description of the Related Art
A memory for an existing mobile phone includes a flash memory for storing a program for controlling the operation and function of the mobile phone and an SRAM (Static Random Access Memory) for executing the program. The flash memory is typically a NOR-type memory that stores user data files as well as the program. The user data may include an address book containing phone numbers and associated user names, e-mail messages and downloaded content from the Internet. In addition to the required operational programs, the memory may also store on-screen images and icons to be used during operation and programming of the phone.
FIG. 1 is a block diagram illustrating a mobile phone 100 employing a conventional memory device 15.
Referring to FIG. 1, a microprocessor (MPU) 20 provides overall control to the operation of the mobile phone 100 by a control program stored in the memory device 15. An analog circuit 40 provides an air-interface to a mobile communication system via antenna ANT and a user-interface 50 provides an interface for a user through an LCD display, keypad, and microphone. A power and reset circuit 60 is provided to reset and initialize the MPU 20 and memory 15 upon start-up of the mobile phone 100. The memory device 15 includes a NOR-type flash memory 10 for storing application programs and user data and a Random Access Memory (RAM) for executing the programs.
In the conventional memory as shown in FIG. 1, the NOR-type flash memory 10 is simply attached to a microprocessor (MPU) 20 so that upon the mobile phone 100 resetting, the MPU 20 generates a dedicated reset vector address, reads a program code from the flash memory 10, and performs a program in the RAM 30 according to a program sequence. Moreover, all user data received through the air, via an antenna ANT, or downloaded from a PC (personal computer) are stored in the NOR-type flash memory 10 being a non-volatile one to be available to a user when necessary.
Storage of user data as well as program data in the NOR-type flash memory imposes cost and space constraints on the manufacture of the existing mobile phone. Especially due to the rising demand for multimedia functions in the mobile phone, the conventional memory structure has the problem that an expensive memory is used for simply storing data. For example, a 4 Mb or above memory is typically used to store one MP3 file.
Therefore, a need exists for a low-cost, large capacity memory device which occupies the same area or smaller than that of a conventional memory device.